The controls of food selection and ingestion are of major importance to human and animal health. Disturbances of the controls of ingestion occur in many human illnesses and may be pathogenic for some. The brain is ultimately responsible for controlling food intake. Nevertheless, the forebrain is the only brain area where control of ingestion has been studied extensively. The overall goal of this work is to better understand the roles of the most caudal part of the brain (hindbrain) in control of ingestion. The proposal focuses on understanding the role of the area postrema and adjacent solitary nucleus in the control of ingestion. Specifically, the experiments proposed will 1) determine which neural connections of this region are responsible for the individual ingestive changes observed after damage to the area postrema and solitary nucleus and 2) attempt to identify chemically discrete neuronal populations which mediate the effects of this brain region on food intake. These studies will be among the first to analyze the role of the hindbrain in the control of hunger and appetite. Such an analysis is important because some controls of appetite seem to arise from the hindbrain and all controls of appetite must be executed via the hindbrain.